The present invention relates generally to a molar tube, and more particularly to a molar tube that is adapted to receive an archwire. More particularly still, the invention relates to a molar tube that facilitates the withdrawal or adjustment of an archwire after the archwire has been employed in an orthodontic treatment. The invention allows an archwire to be locked in the molar tube, thus preventing slippage.
During orthodontic treatment and the use of fixed appliances on the teeth, including brackets for receiving an archwire, molar tubes are employed to anchor the distal ends of the archwire. The molar tubes are mounted on molar teeth, which constitute the posterior teeth in the mouth. Following the placement of the distal ends of the archwire in molar tubes, it is customary to trim the ends of the wire and then bend the ends that protrude from the distal ends of the tubes to prevent the archwire from moving mesially through the tubes which could result in spaces opening mesial to the anchor molars. The archwire is otherwise secured to brackets on the adjacent posterior and anterior teeth, and therefore it is important not to allow mesial movement of the archwire when the fixed appliances are in place. Additionally, in prior art methods, the distal ends of the archwire are bent in a direction to prevent the ends from striking/irritating the patient""s hard or soft tissues, the hard tissues being the enamel surfaces of the teeth, and the soft tissues being the gingiva or cheek.
During the course of treatment using molar tubes of the prior art, it is often necessary to remove and replace the archwires with the bent ends. Such a procedure requires straightening the bent ends as much as possible and then pulling those bent ends mesially through the molar tubes. Inasmuch as it is difficult, if not impossible, to completely straighten the ends of the wires, considerable forces are required to withdraw or pull the wires through the tubes. High amounts of force are first required to deflect the end of the wire so it can pass through the tube and second to overcome the friction created by drawing the deformed wire through the length of the tube. This is particularly the case where full size rectangular archwires are employed to fit rectangular tubes, wherein the tolerances are +xe2x88x920.0.001 inch (0.025 mm). The application of the necessary forces to remove archwires having bent ends is often quite discomforting to the patient. It not only is discomforting by the force required but also because of the duration of that force as the archwire is pulled through the entire length of the tube. The well-being and comfort of a patient is particularly important as it can relate to the results achieved during orthodontic treatment.
Heretofore, there have been molar tubes for receiving archwires and having flared openings at the mesial end to facilitate the threading of the archwire into the tube, such as shown in U.S. Pat. No. 5,556,277. There have also been a number of molar tubes for lip bumpers and head gear having the inlet mesial end enlarged to facilitate the mounting of a lip bumper or head gear, such as shown in U.S. Pat. Nos. 3,815,238; 4,963,092; 5,057,012; 5,151,028; and 5,292,248. It is also known to provide a bracket that permits limited tipping relative to the archwire, as disclosed in U.S. Pat. Nos. 4,842,512; 4,859,179, and 4,877,398.
U.S. Pat. No. 4,355,975 teaches an orthodontic appliance that comprises a plate bonded to a tooth. The plate is connected to the main body of the bracket. The covering orthodontic cap for fixing the wire is connected to the main body of the bracket. The cap can be removed from the bracket since it is fixed and connected thereto with a connecting part and elastic connecting device. The bracket or the cap is provided with a shearing groove that prevents the caps from sliding off and provides for locking and removal of the cap by simple operations.
U.S. Pat. No. 4,424,032 discloses an orthodontic jaw correction appliance comprising a positioning means operatively disposed between the upper and lower dental arches. The positioning means includes a pair of cooperatively engaged elements, one of which is associated with one arch and the other of which is associated with the other arch. The elements are operable as the jaw closes to translate the natural jaw closure force into a corrective force component acting between the two arches. The improvement for operatively relating one element to its associated arch comprises a generally U-shaped splint comprising a generally U-shaped molded plastic body conforming to the general U-shape of the associated arch for application to the cusps of teeth thereof including molar teeth on laterally opposite sides and all teeth mesial to the molar teeth. There is bonding means disposed on the U-shaped molded plastic body for bonding the molded plastic body to the cusps of the teeth so that the splint acts through the bonding means stabilizes the molar teeth and all teeth mesial thereto as a unit to effect jaw correction. The one element and the splint have a point of operative coupling which is mesial to the point of bonding of the splint to at least some of the molar teeth.
U.S. Pat. No. 4,988,292 sets forth an abutment for an orthodontic anchorage that is mountable on an osseointegrated dental implant fixture in the same manner as are components which are used to support prosthodontic restorations. The abutment of the invention is adjustable around the axis of the implant fixture, and it supports a mount for holding an orthodontic anchor fixed to a buccal or a lingual side of the abutment. The mount is adjustable around an axis running between the buccal and lingual surfaces.
U.S. Pat. No. 5,057,012 describes a molar tube for a lip bumper or a face bow comprising: 1) a base having a lingually-facing attaching surface for attaching to a tooth; 2) an elongated, mesioldistally-extending tubular body projecting buccally from the base, wherein the body includes an opening therethrough for receiving the distal ends of a lip bumper or a face bow, and having an inside lingual wall and an outside buccal wall. The opening is flared from the distal end to the mesial end such that the mesial end is larger than the distal end, and of a size substantially larger than the distal end of a lip bumper or a face bow. The distal end of the opening is round and sized to closely receive the distal end of the lip bumper or face bow to provide lateral control. The mesial end is oval and has a vertical dimension adapted to closely receive the distal end of the lip bumper or face bow to control tipping, and the long axis of the oval mesial end extends generally horizontally, whereby insertion of a distal end of a lip bumper or a face bow is greatly enhanced.
U.S. Pat. No. 5,071,345 teaches a prefabricated dental crown analog having an exterior size and contour to approximate the dimensions and shape of a natural tooth at the site, and an orthodontic wire anchor consisting essentially of hollow tubular means providing an integral passage extending mesially-distally through the analog closer to one of the exterior buccal or lingual surfaces than to the center thereof, for passage of an orthodontic wire through the passage whereby the wire may be anchored with the crown analog. The crown of the invention is intended for use in the mouth of a patient having an endosseous dental implant fixture or the like installed in the patient""s jawbone at an edentulous site.
U.S. Pat. No. 5,681,164 discloses and orthopaedic modular assembly comprising: 1) a housing component of rigid material providing a first passage; 2) a second component in the form of a lingual pad support having a first arm adapted to form a snug sliding fit within the first housing passage; 3) a second arm extending at an angle to the first arm, and adapted to conform to the line of one side of a patient""s mouth; and 4) a latch means associated with the housing component, whereby the first arm of the second component is held within the first passage of the housing component by the latch means and is slidably adjustable relative to the housing component to any one of a plurality of predetermined latched positions.
U.S. Pat. No. 5,727,941 provides an implant arrangement for securing a denture to a jawbone, the implant arrangement comprising: 1) an implant shaft means having a central axis, a first end for insertion into the jawbone and a second end; 2) a securing means including a threaded bore formed at the second end for securing the denture thereto, the threaded bore being inclined with a predetermined angle relative to the central axis; 3) an insertion tool means for inserting the implant shaft means into the jawbone, wherein the insertion tool means has a central axis and a first end removably connected to the implant shaft for rotationally inserting the implant shaft into the jawbone; and 4) a connection means formed at the first end of the insertion tool means with an inclination relative to the central axis of the insertion tool means corresponding to the predetermined angle, the connecting means removably interfacing the insertion tool means and the implant shaft, wherein the central axis of the insertion tool means is coaxial with the central axis of the implant shaft.
U.S. Pat. No. 6,036,488 shows a pivotal mounting boss assembly for attachment to an orthodontic band for the pivotal mounting boss of an arch expansion appliance comprising: 1) a base casing, including a base segment for attachment to the orthodontic band, the base segment having an opening formed therein, the opening disposed to attach an arch wire; 2) a body segment being narrower in at least one cross sectional dimension than the base segment, and the body segment having a threaded bore formed therein; and 3) a screw threadedly engaged in the threaded bore, the screw disposed to attach to an eyelet of an expansion appliance.
U.S. Pat. No. 6,217,323 teaches an orthodontic dental distractor for rapid orthodontic tooth movement into a fresh extraction socket. The device includes: 1) a screw bar and a screw nut fixedly engaged with one end of the screw bar; 2) a first joint engageable with one end of the screw bar next to the screw nut and a first hook engageable with a canine band mounted on a canine; and 3) a second joint that is engageable with another end of the screw bar and has a second hook engageable with a molar band mounted on a molar. By turning the screw nut, the screw bar will move the first joint towards the second joint, thus moving the canine rearward toward the molar.
Even where the bent end of an archwire used in conjunction with prior art molar tubes is attempted to be straightened in the mouth, it is virtually impossible to completely straighten the wire, and therefore withdrawal of such an archwire from a tube requires the application of some force to the tube on withdrawal. That force, as applied to the tooth, results in discomfort to the patient.
It is therefore an object of the present invention to provide a new and improved molar tube for archwires that significantly decreases or eliminates the required force when removing an archwire from the tube.
A further object of the present invention is to provide a new and improved molar tube for archwires that reduces the force needed to withdraw a bent archwire from the tube and permits free distal crown tipping of the tooth on which the tube is mounted, thereby favorably contributing to the results obtainable during treatment.
A further object of the present invention is to provide a molar tube for archwires that is patient-friendly to reduce the forces required to withdraw a bent archwire from the tube during visits with the orthodontist, thereby reducing patient discomfort.
A further object of the invention is to allow an archwire to be secured to the molar teeth to provide superior anchorage over cinching the distal ends of the arch wire, i.e., so as to not allow molar teeth to drift forward if so desired. A molar tube lock according to the invention acts as a molar stop.
Another object of the invention is to provide an alternative means to achieve retraction and closure of spaces mesial to the molar teeth. With a properly designed archwire and appropriate loops, the molar stop can secure an activated archwire to close spaces, essentially working similar to a tie back with ligature wire.
Another object of the invention is to prevent the need for omega loops and other such bends designed as molar stops, to prevent mesial movement of the molar teeth.
Another object of the invention is to enable archwire to be secured to allow for advancement of anterior teeth by locking the archwire to the molar tubes and allowing the archwire to extend slightly in front of anterior brackets, as in cases of class II, div. II diagnoses. Molar teeth, due to their size and anatomy are generally used for anchorage. Smaller teeth in front are moved essentially because the larger tooth is more positionally stable to applied forces. Loss of anchorage, or slippage of the molar teeth forward is desirable in some cases. Thus, a molar tube lock according to the invention would not be activatedxe2x80x94to allow free movement of the archwire through the tube, i.e., molars move forward to close space versus anterior teeth moving backward to close the space. A molar tube lock according to the invention can be used afterwards, to prevent re-opening of spaces. Thus, the present invention is universal and can be used in all situations requiring advancement arches, retraction arches, reinforcement of molar anchorages, and prevention of spaces re-opening.
Another object is to provide a molar tube lock that allows the straight wire technique of orthodontic treatment to operate more efficiently.
Other objects, features and advantages of the invention will be apparent from the following detailed disclosure, taken in conjunction with the accompanying sheets of drawings, wherein like reference numerals refer to like parts
The above-mentioned problem of patient discomfort is solved by the present invention wherein a molar tube according to the present invention eliminates the need to bend archwires, as is the case when using molar tubes of the prior art, and thus inherently eliminates the use of force otherwise needed to mesially withdraw a bent archwire from the tube.
More particularly, a molar tube according to the present invention includes a lumen and a threaded boss comprising a threaded hole, wherein the axis of the threaded hole in the boss is disposed at an angle of approximately 45xc2x0 to the axis of the lumen. Such an arrangement allows for the selective securing of an archwire at a desired position/tension within the lumen, while providing control over labiolingual and occlusogingival archwire movement for either round and rectangular archwires, and also torque control for rectangular archwires. Under such an arrangement, the force required to mesially withdraw a bent archwire through the tube is dramatically reduced, if not wholly eliminated in most cases.
The amount of initial force to draw the bent end of an archwire into the molar tube of the present invention and the subsequent force thereafter required to pull the archwire the full length of the tube and remove it from the tube may be reduced to a level of about 0 to 5 percent of what would normally be required with a conventional molar tube. This force reduction translates into enhanced patient comfort.
In its simplest form, a molar tube according to the present invention comprises a base portion having a first face portion that is adapted to be adhered to a molar tooth, a second face portion, and a mesial-distal length dimension. There is a body portion disposed on the second face portion of the base portion, and the body portion comprises an upper portion and a lower portion. The body portion further comprises a lumen that is adapted to receive an archwire, wherein the lumen has an axis which substantially coincides with the mesial-distal length dimension of the base portion. The body portion further comprises a boss comprising a threaded bore that is adapted to receive a setscrew, wherein the threaded bore has an axis. The axis of the threaded bore intersects with the mesial-distal length dimension to form an angle of any degree between 15 degrees and 175 degrees, including every degree therebetween.